1. Field of the Invention
The present invention is related to an electrically-driven hermetic compressor, and more particularly to a suction structure for electrically-driven hermetic compressor which includes a filtering member mounted in an outlet of a suction muffler made of plastic material and an elastic material fitted in an inlet of the suction muffler without a gap therebetween.
2. Description of the Prior Art
In a general electrically-driven hermetic compressor, high temperature heat of refrigerant gas discharged from a discharge muffler is transmitted to a suction muffler. Therefore, the transmitted heat causes temperature of refrigerant gas sucked in the suction muffler to rise thereby reducing coefficient of performance of compressor.
In order to overcome the above problem, there has been continuously studied to mold insulating plastic material, such as polyester resin into a suction muffler. For example, a hermetic refrigeration compressor using this type of plastic suction muffler is disclosed in U.S. Pat. No. 4,370,104.
Referring to FIGS. 1A and 1B, there are shown a conventional electrically-driven hermetic compressor using a plastic suction muffler. As shown in the drawing, the compressor comprises an outer shell 1, a compressor section "A" and a motor "B".
The compressor section "A" includes a cylinder 2, a piston 3, a discharge muffler 4 and a suction muffler 5. The discharge muffler 4 and the suction muffler 5 are spaced from each other at a certain interval and mounted on a cylinder head. As shown FIG. 1B, in the suction muffler 5 is inserted an elastic material 7 fitted in a suction pipe 6 with a certain circumferential gap therebetween.
The motor "B" includes a stator 8 and a rotator 9. A crank shaft 10 is fitted in the rotator 9 and thus rotated by rotation of the rotator 9. A crank pin 10a is eccentrically fixed to a head of the crank shaft 10 relative to the center of crank shaft 10 and thus eccentrically rotated by the rotation of crank shaft 10. A connecting rod 11 is connected between the crank pin 10a and the piston 10 to reciprocate the piston as result of the eccentric rotation of the crank pin 10a. The outer shell 1 contains refrigeration oil 12 at its lower part.
In operation of the above mentioned hermetic compressor, as the rotator 9 of the motor "B" is rotated due to supply of electric current, the crank pin 10a fixed to the crank shaft 10 is eccentrically rotated. The rotating force of crank shaft 10 is transmitted to the piston 3 through the crank pin 10a, thereby causing the piston 3 to be reciprocated in the cylinder 2.
As the piston 3 is reciprocated in the cylinder 2, refrigerant in the cylinder 2 is compressed and continuously sucked in and discharged from the cylinder 2. As a result, refrigerant and refrigerating oil is introduced into the plastic suction muffler 5 through the elastic material 7 and then sucked in the cylinder 2.
In the above hermetic compressor, since a gap of about 2-3 mm is maintained between the elastic material 7 and the suction muffler 5, refrigerant and refrigerating oil are sucked in the suction muffler 5 together and then the refrigerating oil drops into interior of the outer shell 1 through the gap and is collected in the outer shell 1.
However, since the conventional electrically-driven hermetic compressor vibrates upward and downward during operation, interference occurs due to the gap between the plastic suction muffler and the elastic material and thus the plastic suction muffler is damaged or generates its plastic chips due to the interference. Also, since some of refrigerating oil contained in suction gas is introduced into the cylinder and circulated together with refrigerant, performance of the compressor is reduced.